There is proposed a prior velocity detection circuit adapted to detect a moving velocity of a spot such as an optical spot, for example, and a moving direction thereof from two phase signals of sine wave having an advance of phase reversed in accordance with its moving direction and a period inversely proportional to its moving velocity. The moving velocity is detected as a value of voltage by using a frequency/voltage converter (F/V converter) and the moving direction is detected as a two value signal by using a phase comparator.
However, since the frequency/voltage converter and the phase comparator are used, the apparatus is expensive to manufacture. Furthermore, if a velocity control circuit of negative feedback control is constructed by using the detected signals, a path through which the signals pass is required to be switched in accordance with the moving direction, which causes the control circuit to be complicated.